LazyTools

🔒 Every tool runs in your browser — the files and values you enter are never uploaded to any server. How it works

Unit & Measurement Converters

Convert between metric, imperial and US units instantly. Every converter uses the exact internationally defined factors, shows you the formula, and runs entirely in your browser — nothing is uploaded, ever.

Browse by measurement

Most-used conversions

Convert with confidence

A unit conversion is only as good as the factor behind it, and small errors compound — mixing up US and imperial gallons, or fluid ounces of weight and volume, is a classic source of ruined recipes and wrong dosages. Every converter here uses the exact, internationally-defined factor (NIST and BIPM values), so a mile is precisely 1.609344 km and a US gallon is exactly 3.785411784 litres — not a rounded approximation. Where two systems share a name but differ, such as the US versus UK gallon or the metric versus US cup, the tools keep them distinct and flag the difference.

Each conversion is instant and two-way: type a value on either side and the other updates, with the factor and a short explanation shown so you can see how it was derived. It all runs in your browser — nothing is uploaded, and the pages work offline. For cooking-specific measures see Cooking & Kitchen, and for ring, shoe and clothing sizes across regions see Size Converters.

Frequently asked questions

Are these unit converters accurate?

Yes. Every conversion uses the exact, internationally agreed definition of each unit (for example, 1 inch = 25.4 mm exactly and 1 lb = 0.45359237 kg exactly). Results are computed to your chosen precision with no rounding surprises.

Is anything I type sent to a server?

No. All conversions run as JavaScript in your browser. LazyTools has no conversion server — the pages even work offline once loaded.

Why use this instead of asking an AI chatbot?

Speed and reliability: the converter gives an exact, deterministic answer instantly, shows the formula, and never miscalculates. Language models can make arithmetic mistakes and are slower for a simple conversion.